1. Technical Field
The present invention relates to roast and ground coffee products comprising aggregated coffee flake particles which comprise a plurality of compressed coffee flakes bonded together. The aggregated flake coffee products provide improved extractability of the water-soluble flavor constituents, superior initial aroma levels and acceptable bed permeabilities. The present invention also relates to a novel process for preparing the aggregated flake coffee particles by the roll milling of a cold processed coffee feed blend of ground coffees having differing moisture contents under particular roll mill operating conditions.
2. Background Art
Roast and ground coffee which has been transformed into flaked coffee by roll milling the roast and ground coffee is known in the art (see, for example, U.S. Pat. No. 1,903,362, issued Apr. 4, 1933 to R. B. McKinnis, and U.S. Pat. No. 2,368,113, issued Jan. 30, 1945 to C. W. Carter). An improved flaked roast and ground coffee of enhanced extractability is disclosed by Joffe in U.S. Pat. No. 3,615,667, issued Oct. 26, 1971, as well as a method for its production in U.S. Pat. No. 3,660,106, issued May 2, 1972 to J. R. McSwiggin et al.
Art attempts are realizing superior roast coffee products have included improving other coffee attributes in addition to improving the extractability of those flavorful water-soluble coffee constituents often referred to as coffee brew solids. A visually appealing, high-sheen flaked roast and ground coffee of improved extractability of its brew solids is disclosed in U.S. 4,110,485, issued Aug. 29, 1978 to D. R. Grubbs. A flaked coffee product with large visually distinctive flakes can be prepared by flaking a mixture of two roast and ground coffee blends of equal weight fractions. The two coffee blends differ only in their moisture content; one being a high moisture (5.0% by weight) coffee, and one being a low moisture coffee (3% by weight).
While flaking can provide roast coffee in a form which provides certain benefits such as increased extractability and can be used to provide visually distinctive coffee products, coffee flaking can detrimentally affect certain attributes of roast and ground coffee. Flaking is known, for example, to reduce the initial aroma level of packaged coffee as well as to affect the quality of the aroma. To minimize the aroma penalty exacted by flaking, mixtures of conventional roast and ground coffee and of flaked coffee have been formulated (see, for example, U.S. Pat. No. 3,615,667 issued Oct. 26, 1971 to F. M. Joffe). However, such mixtures merely trade off increased initial aroma for increased extractability when conventional roast and ground coffee which has a higher aroma level is substituted for flaked coffee which has higher extractability.
The initial aroma level of flaked coffee could be increased by the simple addition of a highly aromatized carrier oil such as is disclosed in U.S. Pat. No. 3,769,032, issued Oct. 30, 1973 to Lubsen et al. Such an addition, however, would undesirably increase the oil level of the coffee itself as well as any coffee brew made therefrom. Moreover, the aroma material from relatively large quantities of donor coffee must be collected in order to aromatize small quantities of flaked coffee.
A variety of non-donative or unadulterating aromatization methods are known in the art for increasing the aroma of roast and ground coffee. Typically, these methods involve reducing the working temperature of coffee at various stages of processing such as grinding. The cooler working temperatures reduce losses of the volatile aroma materials during these steps (see, for example, U.S. Pat. No. 1,924,059, issued Aug. 22, 1933 to W. Hoskins). These cold grinding processes for conserving aroma have not been applied to minimizing the aroma losses of flaked coffee, apparently, because, as noted above, flaking is known to reduce the level of coffee aroma. Thus, any increase in the aroma of roast and ground coffee apparently would be lost during flaking. However, it has been surprisingly discovered that application of pre-flaking, non-donative aroma conservation methods such as cold processing can provide an increase in the initial aroma level of flaked coffee.
Such a combination of aroma conservation and flaking methods is, however, not made without certain difficulties. An unforeseen disadvantage associated with flaked coffee which has been cold processed is a dramatic decrease in the bed permeability of a coffee product produced. Such decreases in bed permeability lead to unacceptably long drain times needed to prepare coffee brews.
Given the state of the coffee flaking art as described above, there is continuing need for new and useful roast coffee products which provide increased extractability of the flavorful coffee brew solids and which possess high initial aroma levels. Accordingly, it is an object of the present invention to provide a flaked roast coffee product of increased extractability and enhanced initial aroma.
It is a further object of the present invention to provide roast coffee products of enhanced extractability and initial aroma which are substantially free of additive aroma carrier oils.
It is a further object of the present invention to provide flaked roast coffee products of enhanced extractability and initial aroma which have bed permeabilities great enough to provide acceptable coffee bed draining performance.
It has been surprisingly discovered that the above objects can be realized and superior flaked roast coffee products provided which exhibit both enhanced extractability and initial aroma levels as well as adequate bed permeability by formulating aggregated, mixed-moisture flaked coffee compositions. Such coffee compositions are realized by mixing a low-moisture roast and ground coffee fraction and a high-moisture coffee fraction, each of which has been cold processed to minimize coffee aroma losses, and thereafter flaking the roast and ground coffee mixed-moisture blend under particular roll mill conditions. The novel, mixed-moisture coffee flake aggregates produced surprisingly possess sufficient structural strength and integrity to provide bed permeability equivalent to non-cold processed flaked coffee.